Swab cup



Feb. 14, 1928. 1,659,066

B. F. ZEIGLER, JR

Filed Marbh 9. 1926 2 Sheets-Sheei 1 Feb. 14, 1928. 1,659,066

B. F ZEIGLER, JR

SWAB CUP Filed March 9. 1926 2 Sheets-Sheet Patented Feb. 14, 1928.

,UfdiiTQiD STATES PATENT OFFICE.

BENJAMTH F. ZEIGLER, 333... OF DALLAS, TEXAS, ASSIGNOR TO THEGUIBERSON OOR- PORATION, 03? DALLAS, TEXAS, A CORPORATION OF DELAWARE.

SWAB our.

Application filed. March 9, 1926. Serial No. 93,385.

This invention relates to new and useful improvements in expanding swab cups.

The invention has to do with that type of cup, the outer-surface of which is expanded against the wall of .the'tubing or casing by fluid under pressure withinfthe cup. It has been found that either this lateral or radial pressure or the lateral or radiai expansion of the cup is not equal throughout its active length. This may be due to the variation in thickness of the flexible walls of the cup at its different elevations or horizontal planes or it may be, due to the exterior shape of the cup. The result is excessive wear at those portions of the surface where the greatest expansion is present.

The object of my invention is to provide a swab cup with a reduced portion or portions in its walls, whereby excessive pressure will be absorbed by the expansion of the reduced portion prior to contact with the walls of the tubing or casing, and whereby the pressure will bedistrilmted more evenly over the working surface of the cup, thus reducing wear and bulging.

Another object of the invention is to provide the outer surface of the cup with one or more circumferential depressions or grooves, which are flattened out when the cup is radially expanded, and contact had .with the walls of the tubing or casing without undue abrasion of the cup.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of'the following specification and by reference to the accompanying draw1ngs, 1n which an example of the invention is shown and wherein:

Fig. 1 is a view partially in. elevation and partially in section of a swab cup constructed in accordance with my invention,

Fig. 2 is an enlarged cross-sectional view taken on the line 22 of Fig. 1,

Fig. 3 is a view partially in elevation and partially in section of a modified form,

Fig. 4c is a cross-sectional view taken on the line l e of Fig. 3,

Fig. 5 is a view of another form, and

Fig. 6 is a cross-sectional view taken on the line 66 of Fig. 5.

In the drawings the numeral 10 designates a swab cup formed of rubber, rubber compound, rubberized fabric or any other suitable flexible or elastic material. While I have illustrated the invention in connection with a swab cup, it is not limited to formed with a reduced heel portion 11 seated in a thimble '12 and a mandrel 13. The upper exposed portion of the cup overhangs the thimble'having an annular shoulder 14 at its lower end. Intermediate its ends the said exposed or working surface of the cup has an annular depression or groove 15, at which point the wall of the cup is materially reduced in thickness. 1'

The cup has vertical surface grooves 16 extending from its heel to its lip. Reinforcing wires 17 have toes 18 at their lower ends engaging in seats 19 at the bottoms of the grooves 16. These wires are bent outwardly around the shoulder 14. Normally the wires are not seated in those portions of the grooves 16 which pass across the depression 15.

It will be seen that when the cup 10 is filled with a liquid or fluid under a normal pressure, the walls will remain in substanby the distortion of the walls of the cup. By

this arrangement the outer surface of the cup will not be bulged outward to such an extent as to cause excessive wear, thus prolonging the life of the cup. Sufficient contact above and below the depression 15, will be had under :1 normal pressure, to assure a proper functioning of the cup in the tubing.

In Figs. 3 to 6 inclusive I have shown the invention applied to a cup 10 of the type which has each end confined in a thimble. In Figs. 3 and 4 the cup has an annular or circumferential depression 25 intermediate its ends; while in Figs. 5 and 6 the cup 10 has a pair of annular-depressions 35 intermediate its ends. It is obvious that the latter'form would distort under a much less pressure than the other forms and compenso that the depressions will be flattenedout under a normal pressure, whereby sufficient compensation will be had to ofiset excessive bulging and wear of the surface of the cup.

In nearly every swab cup where the internal pressure of the fluid is utilized to maintain contact between the cup and the casing there exists around the periphery of the cup and usually near the bottom the maximum wear or bulging effect. This naturally shortens the life of the cup as that point will rupture before the rest of the cup isentirely worn out. Since the fluids exert their pressure equally in all directions and the hydrostatic head is greatest at the lowest point of the column, thispressure coupled with the friction of the cup on the walls of the casing, causes the rupturing. The most desi able condition is to have a uniform wear of the cup throughout its entire contact area with the casing.

If the body of the cup is reduced intermediate its normal zones of contact with the casing, the fluid pressure upon the interior of the cup is exerted at these Zones and also acts against the flexible reduced portion to flex the same into contact with the casing or into substantial alineinentwith the normal Zones of contact. The reduced portion being in tension and balanced between the elasticity of the rubber and the fluid pres" sure would therefor have less friction on the walls of the casing than the normal working surfaces and would greatly prolong the life of the cup.

Various changes in the size and shape of the different parts as well as modifications and alterations, may be made within the scope of the appended claims.

What I claim, is:

l. A swab cup comprising a tubular elastic body having a normal working surface and a circumferential depression therein, the body at said depressed portion being expansible laterally by internal pressure into substantial alinement with said working surface.

2. A swab cup comprising a tubular elast-ic body having spaced normal working surfaces and an intermediate annular reduced portion expansible laterally by internal pressure into substantial alinement with said working surfaces.

3. A swab cup of rubber-like material having a transversely yielding wall with a circumferential depression in its normal working surface and provided with vertical grooves extending above and below said depression, and reinforcing. wires embedded in said grooves and bridging said depression.

In testimony whereof I affix my signature.

BENJAMIN F. ZEIGLER, JR. 

